Study On The Method Of Computing Runoff Production For Small Catchment Based On GIS

The distributed hydrological model uses the technology of geographic information system (GIS), remote sensing (RS), at the same time it takes account of the character of the soil, vegetation, topography. Taking Sangyuan Basin as a study area, a rainfall-runoff distributed hydrological model is constructed, which can be used small catchments. The author designs and implements the computing of spatial interpolation of precipitation and the runoff production based on Soil Conservation Services (SCS)method. The author studies the content from two aspects as followed mostly. (1) The author analyzes the relations between hourly precipitation and longitude,latitude,altitude , takes Sangyuan Basin as a sample , uses the technology of spatial information , and raise a developed method, regressive-inverse-distance-squared (RIDS) . The author interpolates the precipitation of Sangyuan Basin using the "Thiessen polygons"method, the inverse-distance-squared (IDS)method, the gradient-plus-inverse-distance-squared (GIDS) method and the RIDS method. The results indicate that the RIDS method is available. (2)After the completion of the spatial interpolation of precipitation, the author computes the effective rainfall using the SCS method. The author got the matrix of curve numbers (CN) using the technology of GIS. The matrix describes the character of the soil more elaborate than the number of "CN". The author computes the effective rainfall of the distributed hydrological model based on grid in the small basin lacking data successfully.